Novel Hydantoin Derivatives as Metalloproteinase Inhibitors

ABSTRACT

The invention provides compounds of formula (I): wherein R 1 , R 2 , A, A 1  and B are as defined in the specification; processes for their preparation; pharmaceutical compositions containing them; a process for preparing the pharmaceutical compositions; and their use in therapy. The compounds are useful as MMP inhibitors.

The present invention relates to novel hydantoin derivatives, processesfor their preparation, pharmaceutical compositions containing them andtheir use in therapy.

Metalloproteinases are a superfamily of proteinases (enzymes) whosenumbers in recent years have increased dramatically. Based on structuraland functional considerations these enzymes have been classified intofamilies and subfamilies as described in N. M. Hooper (1994) FEBSLetters 354:1-6. Examples of metalloproteinases include the matrixmetalloproteinases (MMPs) such as the collagenases (MMP1, MMP8, MMP13),the gelatinases (MMP2, MMP9), the stromelysins (MMP3, MMP10, MMP II),matrilysin (MMP7), metalloelastase (MMP12), enamelysin (MMP19), theMT-MMPs (MMP14, MMP15, MMP16, MMP17); the reprolysin or adamalysin orMDC family which includes the secretases and sheddases such as TNFconverting enzymes (ADAM10 and TACE); the astacin family which includeenzymes such as procollagen processing proteinase (PCP); and othermetalloproteinases such as aggrecanase, the endothelin converting enzymefamily and the angiotensin converting enzyme family.

Metalloproteinases are believed to be important in a plethora ofphysiological disease processes that involve tissue remodelling such asembryonic development, bone formation and uterine remodelling duringmenstruation. This is based on the ability of the metalloproteinases tocleave a broad range of matrix substrates such as collagen, proteoglycanand fibronectin. Metalloproteinases are also believed to be important inthe processing, or secretion, of biological important cell mediators,such as tumour necrosis factor (TNF); and the post translationalproteolysis processing, or shedding, of biologically important membraneproteins, such as the low affinity IgE receptor CD23 (for a morecomplete list see N. M. Hooper et al., (1997) Biochem. J. 321:265-279).

Metalloproteinases have been associated with many diseases orconditions. Inhibition of the activity of one or more metalloproteinasesmay well be of benefit in these diseases or conditions, for example:various inflammatory and allergic diseases such as, inflammation of thejoint (especially rheumatoid arthritis, osteoarthritis and gout),inflammation of the gastro-intestinal tract (especially inflammatorybowel disease, ulcerative colitis and gastritis), inflammation of theskin (especially psoriasis, eczema, dermatitis); in tumour metastasis orinvasion; in disease associated with uncontrolled degradation of theextracellular matrix such as osteoarthritis; in bone resorptive disease(such as osteoporosis and Paget's disease); in diseases associated withaberrant angiogenesis; the enhanced collagen remodelling associated withdiabetes, periodontal disease (such as gingivitis), corneal ulceration,ulceration of the skin, post-operative conditions (such as colonicanastomosis) and dermal wound healing; demyelinating diseases of thecentral and peripheral nervous systems (such as multiple sclerosis);Alzieimer's disease; extracellular matrix remodelling observed incardiovascular diseases such as restenosis and atherosclerosis; asthma;rhinitis; and chronic obstructive pulmonary diseases (COPD).

MMP12, also known as macrophage elastase or metalloelastase, wasinitially cloned in the mouse by Shapiro et al [1992, Journal ofBiological Chemistry 267: 4664] and in man by the same group in 1995.MMP12 is preferentially expressed in activated macrophages, and has beenshown to be secreted from alveolar macrophages from smokers [Shapiro etal, 1993, Journal of Biological Chemistry, 268: 23824] as well as infoam cells in atherosclerotic lesions [Matsumoto et al, 1998, Am. J.Pathol. 153: 109]. A mouse model of COPD is based on challenge of micewith cigarette smoke for six months, two cigarettes a day six days aweek. Wild-type mice developed pulmonary emphysema after this treatment.When MMP12 knock-out mice were tested in this model they developed nosignificant emphysema, strongly indicating that MMP12 is a key enzyme inthe COPD pathogenesis. The role of MMPs such as MMP12 in COPD (emphysemaand bronchitis) is discussed in Anderson and Shinagawa, 1999, CurrentOpinion in Anti-inflammatory and Immunomodulatory Investigational Drugs1(1): 29-38. It was recently discovered that smoking increasesmacrophage infiltration and macrophage-derived MMP-12 expression inhuman carotid artery plaques Kangavari [Matetzky S, Fishbein M C et al.,Circulation 102:(18), 36-39 Suppl. S, Oct. 31, 2000].

MMP9-(Gelatinase B; 92 kDa-TypeIV Collagenase; 92 kDa Gelatinase) is asecreted protein which was first purified, then cloned and sequenced, in1989 [S. M. Wilhelm et al (1989) J. Biol. Chem. 264 (29): 17213-17221;published erratum in J. Biol. Chem. (1990) 265 (36): 22570]. A recentreview of MMP9 provides an excellent source for detailed information andreferences on this protease: T. H. Vu & Z. Werb (1998) (In: MatrixMetalloproteinases, 1998, edited by W. C. Parks & R. P. Mecham, pp.115-148, Academic Press. ISBN 0-12-545090-7). The following points aredrawn from that review by T. H. Vu & Z. Werb (1998).

The expression of MMP9 is restricted normally to a few cell types,including trophoblasts, osteoclasts, neutrophils and macrophages.However, the expression can be induced in these same cells and in othercell types by several mediators, including exposure of the cells togrowth factors or cytokines. These are the same mediators oftenimplicated in initiating an inflammatory response. As with othersecreted MMPs, MMP9 is released as an inactive Pro-enzyme which issubsequently cleaved to form the enzymatically active enzyme. Theproteases required for this activation in vivo are not known. Thebalance of active MMP9 versus inactive enzyme is further regulated invivo by interaction with TIMP-1 (Tissue Inhibitor ofMetalloproteinases-1), a naturally-occurring protein. TIMP-1 binds tothe C-terminal region of MMP9, leading to inhibition of the catalyticdomain of MMP9. The balance of induced expression of ProMMP9, cleavageof Pro- to active MMP9 and the presence of TIMP-1 combine to determinethe amount of catalytically active MMP9 which is present at a localsite. Proteolytically active MMP9 attacks substrates which includegelatin, elastin, and native Type IV and Type V collagens; it has noactivity against native Type I collagen, proteoglycans or laminins.

There has been a growing body of data implicating roles for MMP9 invarious physiological and pathological processes. Physiological rolesinclude the invasion of embryonic trophoblasts through the uterineepithelium in the early stages of embryonic implantation; some role inthe growth and development of bones; and migration of inflammatory cellsfrom the vasculature into tissues.

MMP9 release, measured using enzyme immunoassay, was significantlyenhanced in fluids and in AM supernantants from untreated asthmaticscompared with those from other populations [Am. J. Resp. Cell & Mol.Biol., November 1997, 17 (5):583-591]. Also, increased MMP9 expressionhas been observed in certain other pathological conditions, therebyimplicating MMP9 in disease processes such as COPD, arthritis, tumourmetastasis, Alzheimer's disease, multiple sclerosis, and plaque rupturein atherosclerosis leading to acute coronary conditions such asmyocardial infarction.

A number of metalloproteinase inhibitors are known (see, for example,the reviews of MMP inhibitors by Beckett R. P. and Whittaker M., 1998,Exp. Opin. Ther. Patents, 8(3):259-282; and by Whittaker M. et al, 1999,Chemical Reviews 99(9):2735-2776).

WO 02/074767 discloses hydantoin derivatives of formula

that are useful as MMP inhibitors, particularly as potent MMP12inhibitors.

We now disclose a further group of hydantoin derivatives that areinhibitors of metalloproteinases and are of particular interest ininhibiting MMPs such as MMP12 and MMP9. The compounds of the presentinvention have beneficial potency, selectivity and/or pharmacokineticproperties. The compounds of the present invention are within thegeneric scope of WO 02/074767 but are of a type not specificallyexemplified therein.

In accordance with the present invention, there are provided compoundsof formula (I)

whereinR¹ represents H, halogen, CF₃ or CH₂CN;R² represents C1 to 3 allyl; andA, A¹ and B each independently represent CH or N;and pharmaceutically acceptable salts thereof.

The compounds of formula (I) may exist in enantiomeric forms. It is tobe understood that all enantiomers, diastereomers, racemates andmixtures thereof are included within the scope of the invention.

Compounds of formula (I) may also exist in various tautomeric forms. Allpossible tautomeric forms and mixtures thereof are included within thescope of the invention.

In one embodiment, R¹ represents chloro.

In one embodiment, R¹ represents CF₃.

In one embodiment, R² represents methyl or ethyl. In one embodiment, R²represents methyl.

In one embodiment, A and A¹ each represent N. In another embodiment, Arepresents N and A¹ represents CH. In another embodiment, A and A¹ eachrepresent CH.

In one embodiment, B represents N. In another embodiment, B representsCH.

In one embodiment, R¹ represents CF₃; R² represents methyl or ethyl; Aand A¹ each represent N; and E represents CH.

In one embodiment, R¹ represents CF₃; R² represents methyl or ethyl; Aand A¹ each represent N; and B represents N.

In one embodiment, R¹ represents chloro; R² represents methyl or ethyl;A represents N and A¹ represents CH; and B represents N.

In one embodiment, R¹ represents chloro; R² represents methyl or ethyl;and A, A¹ and B each represent CH.

Unless otherwise indicated, the term “C1 to 3 alkyl” referred to hereindenotes a straight or branched chain alkyl group having from 1 to 3carbon atoms. Examples of such groups include methyl, ethyl, n-propyland i-propyl.

Unless otherwise indicated, the term “halogen” referred to hereindenotes fluoro, chloro, bromo and iodo.

Examples of compounds of the invention include:

-   (5S)-5-methyl-5-({[6-[2-(trifluoromethyl)pyrimidin-5-yl]-3,4-dihydroisoquinolin-2(1H)-yl]sulfonyl}methyl)imidazolidine-2,4-dione;-   (5S)-5-({[6-(4-chlorophenyl)-3,4-dihydroisoquinolin-2(1H)-yl]sulfonyl}methyl)-5-methylimidazolidine-2,4-dione;-   {4-[2-({[(4S)-4-methyl-2,5-dioxoimidazolidin-4-yl]methyl}sulfonyl)-1,2,3,4-tetrahydroisoquinolin-6-yl]phenyl}acetonitrile;-   (5S)-5-methyl-5-{[(6-pyridin-3-yl-3,4-dihydroisoquinolin-2(1H)-yl)sulfony]methyl}imidazolidine-2,4-dione;-   (5S)-5-({[6-(4-chlorophenyl)-3,4-dihydro-2,7-naphthyridin-2(1H)-yl]sulfonyl}methyl)-5-methylimidazolidine-2,4-dione;    and pharmaceutically acceptable salts thereof.

Each exemplified compound represents a particular and independent aspectof the invention.

The compounds of formula (I) may exist in enantiomeric forms. Therefore,all enantiomers, diastereomers, racemates and mixtures thereof areincluded within the scope of the invention. The various optical isomersmay be isolated by separation of a racemic mixture of the compoundsusing conventional techniques, for example, fractional crystallisation,or HPLC. Alternatively the optical isomers may be obtained by asymmetricsynthesis, or by synthesis from optically active starting materials.

Where optically isomers exist in the compounds of the invention, wedisclose all individual optically active forms and combinations of theseas individual specific embodiments of the invention, as well as theircorresponding racemates.

Preferably the compounds of formula (I) have (5S)-stereochemistry asshown below:

Where tautomers exist in the compounds of the invention, we disclose allindividual tautomeric forms and combinations of these as individualspecific embodiments of the invention.

The present invention includes compounds of formula (I) in the form ofsalts. Suitable salts include those formed with organic or inorganicacids or organic or inorganic bases. Such salts will normally bepharmaceutically acceptable salts although non-pharmaceuticallyacceptable salts may be of utility in the preparation and purificationof particular compounds. Such salts include acid addition salts such ashydrochloride, hydrobromide, citrate, tosylate and maleate salts andsalts formed with phosphoric acid or sulphuric acid. In another aspectsuitable salts are base salts such as an alkali metal salt, for example,sodium or potassium, an alkaline earth metal salt, for example, calciumor magnesium, or an organic amine salt, for example, triethylamine.

Salts of compounds of formula (I) may be formed by reacting the freebase or another salt thereof with one or more equivalents of anappropriate acid or base.

The compounds of formula (I) are useful because they possesspharmacological activity in animals and are thus potentially useful aspharmaceuticals. In particular, the compounds of the invention aremetalloproteinase inhibitors and may thus be used in the treatment ofdiseases or conditions mediated by MMP12 and/or MMP9 such as asthma,rhinitis, chronic obstructive pulmonary diseases (COPD), arthritis (suchas rheumatoid arthritis and osteoarthritis), atherosclerosis andrestenosis, cancer, invasion and metastasis, diseases involving tissuedestruction, loosening of hip joint replacements, periodontal disease,fibrotic disease, infarction and heart disease, liver and renalfibrosis, endometriosis, diseases related to the weakening of theextracellular matrix, heart failure, aortic aneurysms, CNS relateddiseases such as Alzheimer's disease and multiple sclerosis (MS), andhaematological disorders.

In general, the compounds of the present invention are potent inhibitorsof MMP9 and MMP12. The compounds of the present invention also show goodselectivity with respect to a relative lack of inhibition of variousother MMPs such as MMP14.

Accordingly, the present invention provides a compound of formula (I),or a pharmaceutically acceptable salt thereof, as hereinbefore definedfor use in therapy.

In another aspect, the invention provides the use of a compound offormula (I), or a pharmaceutically acceptable salt thereof, ashereinbefore defined in the manufacture of a medicament for use intherapy.

In another aspect, the invention provides the use of a compound offormula (I), or a pharmaceutically acceptable salt thereof, ashereinbefore defined in the manufacture of a medicament for use in thetreatment of diseases or conditions in which inhibition of MMP12 and/orMMP9 is beneficial.

In another aspect, the invention provides the use of a compound offormula (I), or a pharmaceutically acceptable salt thereof, ashereinbefore defined in the manufacture of a medicament for use in thetreatment of inflammatory disease.

In another aspect, the invention provides the use of a compound offormula (I), or a pharmaceutically acceptable salt thereof, ashereinbefore defined in the manufacture of a medicament for, use in thetreatment of an obstructive airways disease such as asthma or COPD.

In another aspect, the invention provides the use of a compound offormula (I), or a pharmaceutically acceptable salt thereof, ashereinbefore defined in the manufacture of a medicament for use in thetreatment of rheumatoid arthritis, osteoarthritis, atherosclerosis,cancer or multiple sclerosis.

In the context of the present specification, the term “therapy” alsoincludes “prophylaxis” unless there are specific indications to thecontrary. The terms “therapeutic” and “therapeutically” should beconstrued accordingly.

Prophylaxis is expected to be particularly relevant to the treatment ofpersons who have suffered a previous episode of, or are otherwiseconsidered to be at increased risk of, the disease or condition inquestion. Persons at risk of developing a particular disease orcondition generally include those having a family history of the diseaseor condition, or those who have been identified by genetic testing orscreening to be particularly susceptible to developing the disease orcondition.

The invention further provides a method of treating a disease orcondition in which inhibition of MMP12 and/or MMP9 is beneficial whichcomprises administering to a patient a therapeutically effective amountof a compound of formula (I) or a pharmaceutically acceptable saltthereof as hereinbefore defined.

The invention also provides a method of treating an obstructive airwaysdisease, for example, asthma or COPD, which comprises administering to apatient a therapeutically effective amount of a compound of formula (I)or a pharmaceutically acceptable salt thereof as hereinbefore defined.

For the above-mentioned therapeutic uses the dosage administered will,of course, vary with the compound employed, the mode of administration,the treatment desired and the disorder to be treated. The daily dosageof the compound of formula (I)/salt (active ingredient) may be in therange from 0.001 mg/kg to 75 mg/kg, in particular from 0.5 mg/kg to 30mg/kg. This daily dose may be given in divided doses as necessary.Typically unit dosage forms will contain about 1 mg to 500 mg of acompound of this invention.

The compounds of formula (I) and pharmaceutically acceptable saltsthereof may be used on their own but will generally be administered inthe form of a pharmaceutical composition in which the formula (I)compound/salt (active ingredient) is in association with apharmaceutically acceptable adjuvant, diluent or carrier. Depending onthe mode of administration, the pharmaceutical composition willpreferably comprise from 0.05 to 99% w (percent by weight), morepreferably from 0.10 to 70% w, of active ingredient, and, from 1 to99.95% w, more preferably from 30 to 99.90% w, of a pharmaceuticallyacceptable adjuvant, diluent or carrier, all percentages by weight beingbased on total composition. Conventional procedures for the selectionand preparation of suitable pharmaceutical formulations are describedin, for example, “Pharmaceuticals—The Science of Dosage Form Designs”,M. E. Aulton, Churchill Livingstone, 1988.

Thus, the present invention also provides a pharmaceutical compositioncomprising a compound of formula (I) or a pharmaceutically acceptablesalt thereof as hereinbefore defined in association with apharmaceutically acceptable adjuvant, diluent or carrier.

The invention further provides a process for the preparation of apharmaceutical composition of the invention which comprises mixing acompound of formula (I) or a pharmaceutically acceptable salt thereof ashereinbefore defined with a pharmaceutically acceptable adjuvant,diluent or carrier.

The pharmaceutical compositions of this invention may be administered ina standard manner for the disease or condition that it is desired totreat, for example by oral, topical, parenteral, buccal, nasal, vaginalor rectal administration or by inhalation. For these purposes thecompounds of this invention may be formulated by means known in the artinto the form of, for example, tablets, capsules, aqueous or oilysolutions, suspensions, emulsions, creams, ointments, gels, nasalsprays, suppositories, finely divided powders or aerosols forinhalation, and for parenteral use (including intravenous, intramuscularor infusion) sterile aqueous or oily solutions or suspensions or sterileemulsions.

In addition to the compounds of the present invention the pharmaceuticalcomposition of this invention may also contain, or be co-administered(simultaneously or sequentially) with, one or more pharmacologicalagents of value in treating one or more diseases or conditions referredto hereinabove such as “Symbicort” (trade mark) product.

The present invention further provides a process for the preparation ofa compound of formula (I) or a pharmaceutically acceptable salt thereofas defined above which, comprises:a) reaction of a compound of formula (II)

wherein R² is as defined in formula (I) and L¹ represents a leavinggroup, with a compound of formula (III) (or a salt thereof)

wherein R¹, A, A¹ and B are as defined in formula (I); orb) reaction of a compound of formula (V)

wherein R² and B are as defined in formula (I) and LG is a leavinggroup; with a boronic acid derivative of formula (XII)

wherein R¹, A and A¹ are as Defined in Formula (I); orc) reaction of a compound of formula (IX)

wherein R¹, R², A, A¹ and B are as defined in formula (I); with ammoniumcarbonate and potassium cyanide;and optionally thereafter forming a pharmaceutically acceptable saltthereof.

In the above process (a), suitable leaving groups L¹ include halo,particularly chloro or trifluoromethylsulfonate. The reaction ispreferably performed in a suitable solvent optionally in the presence ofan added base for a suitable period of time, typically 0.5 to 16 h, atambient to reflux temperature. Typically solvents such asN,N-dimethylformamide, pyridine, tetrahydrofuran, acetonitrile,N-methylpyrrolidine or dichloromethane are used. When used, the addedbase may be an organic base such as triethylamine,N,N-diisopropylethylamine, N-methylmorpholine or pyridine, or aninorganic base such as an alkali metal carbonate. The reaction istypically conducted at ambient temperature for 0.5 to 16 h, or untilcompletion of the reaction has been achieved, as determined bychromatographic or spectroscopic methods. Reactions of sulfonyl halideswith various primary and secondary amines are well known in theliterature, and the variations of the conditions will be evident forthose skilled in the art.

Sulfonylchlorides of formula (II) wherein L¹ represents chloro and R²represents Me are disclosed in WO 02/074767 and references citedtherein. Corresponding compounds wherein R² represents C1 to 3 alkyl maybe prepared using analogous methods.

Suitable processes for the preparation of compounds of formula (I) aredescribed in a retrosynthetic way in Scheme 1.

In Scheme 1, protecting groups (PG) can be either carbamates (e.g.tert-butoxycarbamate), amides (e.g. trifluoroacetyl) or alkyl (e.g.tert-butyl or benzyl). Leaving groups (LG) can be either chloride,bromide, iodide or trifluoromethylsulfonate. In the palladium-catalysedSuzuki couplings, either boronic acids or pinacolboronates may be used.Intermediate (IVa-c) can be prepared by standard Suzuki coupling (Chem.Rev. 1995, 95, 2457) between an electrophile (VIIa-c) and a boronreagent (XII), or the other way around, between an electrophile (XI) anda boron reagent (VIIIa-c). The latter can be obtained from (VIIa-c)using standard Miyaura conditions (J. Org. Chem. 1995, 60, 7508-7510).Deprotection of (IVa-c) either by hydrogen chloride in methanol(PG=tert-butoxycarbonyl) or refluxing 1-chloroethylchloroformate/refluxing methanol (PG=tert-butyl or benzyl) (Synlett.1993, 195-196) gives amine (IIIa-c) as a hydrochloride salt. The freebase can be obtained by treatment of (IIIa-c) with base and extractionwith an organic solvent such as ethyl acetate or toluene. Reacting(IIIa-c) either as a salt or base in a suitable solvent (e.g.acetonitrile, tetrahydrofuran, N-methylpyrrolidine orN,N-dimethylformamide) with the sulfonyl chloride (II) in the presenceof a tertiary amine (e.g. triethylamine, pyridine orN,N-diisopropylethylamine) for 0.5 to 16 hours produces compounds offormula (I).

An alternative route to compounds of formula (I) from intermediate(IIIa-c) via methanesulfonamide (Xa-c) and ketone (IXa-c) has beenpreviously described (WO 02/074767). Briefly, treatment of (IIIa-c) withmethansulfonyl chloride and a tertiary amine (e.g. triethylamine,pyridine or N,N-diisopropylethylamine) in a suitable solvent (e.g.dichloromethane or tetrahydrofuran) produces the methansulfonamide(Xa-c) which in turn can be transformed into the ketone (IXa-c) usingstandard procedures. Heating ketone (IXa-c) with ammonium carbonate andpotassium cyanide in 50% aqueous ethanol in a sealed vial at 80-90° C.for 1 to 5 hours gives a racemic hydantoin that can be resolved bychiral chromatography (e.g. on OD-H with 100% ethanol).

In a third route, intermediate (VIIa-c) is deprotected as describedabove to give amine (VIa-c) as a hydrochloride salt. The free base canbe isolated by treatment with base and extraction with an organicsolvent e.g. ethyl acetate or toluene. Reacting (VIa-c) either as a saltor base in a suitable solvent (e.g. acetonitrile, tetrahydrofuran,N-methylpyrrolidine or N,N-dimethylformamide) with sulfonyl chloride(II) in the presence of a tertiary amine (e.g. triethylamine, pyridineor N,N-diisopropylethylamine) for 0.5 to 16 hours produces chiralsulfonamide (Va-c). The latter can be coupled with boron reagent (XII)using standard Suzuki conditions to give compounds of formula (I).

Intermediates (VIIa-b) are conveniently prepared using the followingmethods.

The 1,2,3,4-Tetrahydroisoquinoline Intermediate (VIIa)

Methods for the synthesis of 1,2,3,4-tetrahydroisoquinolines are wellknown in the literature. The classical route is the Pomeranz-Fritzreaction of benzaldehydes with a diacetal protected aminoacetaldehyde(Org. React. 1951, 6, 191) yielding the isoquinoline nucleus which uponcatalytical reduction gives 1,2,3,4-tetrahydro-isoquinolines. Anotherroute is the Bischler-Napieralski reaction (Org. React. 1951, 6, 74) ofa carbamate of 2-phenylethanamines with phosphoryl chloride in refluxingtoluene or xylenes. Reduction of the resulting cyclic benzamide withlithium aluminium hydride in tetrahydrofuran (J. Med. Chem. 1987,30(12), 2208-2216) or diborane in tetrahydrofuran (J. Med. Chem. 1980,23(5), 506-511) affords the 1,2,3,4-tetrahydroisoquinoline. A variationof the Bischler-Napieralski reaction is the Pictet-Spengler synthesis(Org. React. 1951, 6, 151). In this reaction amides, carbamates orsulfonamides of 2-phenylethanamines are heated with paraformaldehyde andstrong proton acids (e.g. trifluoroacetic acid, sulfuric acid) or Lewisacids in a solvent (e.g. dichloromethane, toluene, formic acid) to givethe 1,2,3,4-tetrahydroisoquinoline in a single step (Tetrahedron 2002,58(8), 1471-1478).

Preferably the 1,2,3,4-tetrahydroisoquinoline intermediate (VIIa) issynthesised by Route A shown in Scheme 2. This route is aFriedel-Craft-type reaction ofN-[2-(3-bromophenyl)ethyl]-2,2,2-trifluoroacetamide with formaldehydeand sulfuric acid in acetic acid (Tetrahedron Lett. 1996, 37(31),5453-5456) giving a mixture of the 6-bromo- and 8-bromoisomer in a ratioof 3 to 1. Replacement of the trifluoroacetamide group with a BOC-groupgives (VIIa). The regioisomers are not conveniently separated at thisstage.

The 1,2,3,4-tetrahydro-2,7-naphthyridine Intermediate (VIIb)

In contrast to the 1,2,3,4-tetrahydroisoquinolines, there are rather fewexamples of synthetic methods for 1,2,3,4-tetrahydro-2,7-naphthyridinesin the literature. One important method to prepare1,2,3,4-tetrahydro-2,7-naphthyridine is the regio-selective catalyticreduction of 2,7-naphthyridine (Eur. J. Med. Chem. Ther. 1996, 31(11),875-888). The synthesis of 2,7-naphthyridine and some derivativesthereof has been described in the literature. One classical routeinvolves several steps and starts with the acid catalysed condensationof malononitrile with diethyl 1,3-acetonedicarboxylate (J. Chem. Soc.1960, 3513-3515; see also J. Heterocycl. Chem. 1970, 7, 419-421). Aslightly different route to 2,7-naphthyridine involves oxidation of4-formyl-2,7-naphthyridine to give 2,7-naphthyridine-4-carboxylic acidfollowed by decarboxylation (Synthesis 1973, 46-47). A completelydifferent method is based on the internal Diels-Alder reaction ofN-(ethoxycarbonyl)-N-(but-3-ynyl)amino-methylpyrazine and gives amixture of 1,2,3,4-tetrahydro-2,7-naphthyridine and5,6,7,8-tetrahydro-1,7-naphthyridine after hydrolysis of the carbamategroup (WO 02/064574).

Preferably the 1,2,3,4-tetrahydro-2,7-naphthyridine intermediate (VIIb)can be synthesised as shown in Schemes 3 and 4. In Route B, commerciallyavailable 6-methoxynicotinaldehyde is treated successively with thelithium salt of N,N,N′-trimethylethylenediamine, then n-BuLi in hexanesand finally iodine to afford the 4-iodo-6-methoxynicotinaldehyde (cf.Tetrahedron Lett. 1993, 34(39), 6173-6176). The iodo compound is coupledwith trimethylsilylacetylene under usual Sonagashira-Hagihara conditions(Synthesis 1980, 627-630) and the resulting6-methoxy-4-[(trimethylsilyl)ethynyl]nicotinaldehyde is condensed withammonium hydroxide in ethanol to give 3-methoxy-2,7-naphthyridine(Synthesis 1999, 2, 306-311). Regioselective catalytical reduction (cf.Eur. J. Med. Chem. Ther. 1996, 31(11), 875-888) affords6-methoxy-1,2,3,4-tetrahydro-2,7-naphthyridine. Demethylation andN-protection with BOC-anhydride and finally treatment of the resultingtert-butyl 6-hydroxy-3,4-dihydro-2,7-naphthyridine-2(1H)-carboxylatewith triflic anhydride in a two-phase system gives (VIIb).

In Route C, commercially available 5-bromo-2-methoxy-4-methylpyridine inanhydrous tetrahydrofuran is metallated with n-BuLi and then treatedwith N,N-dimethylformamide to afford 6-methoxy-4-methylnicotinaldehyde.This was converted to the tert-butylimine with tert-butylamine indichloromethane. Metallation with lithium 2,2,6,6-tetramethylpiperidide(Li-TMP) (cf. J. Org. Chem. 1993, 58, 2463-2467) and addition ofN,N-dimethylformamide affords the iminoacetaldehyde which is reducedwith sodium cyanoborohydride in methanol to give2-tert-butyl-6-methoxy-1,2,3,4-tetrahydro-2,7-naphthyridine. Cleavage ofthe methyl group with refluxing 48% hydrobromic acid and treatment withtriflic anhydride in the presence of base gives (VIIb) protected as thetert-butylamine.

It will be appreciated by those skilled in the art that in the processesof the present invention certain potentially reactive functional groupssuch as hydroxyl or amino groups in the starting reagents orintermediate compounds may need to be protected by suitable protectinggroups. Thus, the preparation of the compounds of the invention mayinvolve, at various stages, the addition and removal of one or moreprotecting groups.

Suitable protecting groups and details of processes for adding andremoving such groups are described in ‘Protective Groups in OrganicChemistry’, edited by J. W. F. McOmie, Plenum Press (1973) and‘Protective Groups in Organic Synthesis’, 3rd edition, T. W. Greene andP. G. M. Wuts, Wiley-Interscience (1999).

The compounds of the invention and intermediates thereto may be isolatedfrom their reaction mixtures and, if necessary further purified, byusing standard techniques.

The present invention will now be further explained by reference to thefollowing illustrative examples.

General Methods

¹H NMR and ¹³C NMR spectra were recorded on a Varian Inova 400 MHz or aVarian Mercury-VX 300 MHz instrument. The central peaks of chloroform-d(δ_(H) 7.27 ppm), dimethylsulfoxide-d₆ (δ_(H) 2.50 ppm), acetonitrile-d₃(δ_(H) 1.95 ppm) or methanol-d₄ (δ_(H) 3.31 ppm) were used as internalreferences. Column chromatography was carried out using silica gel(0.040-0.063 mm, Merck) with a slight over-pressure (0.2-0.4 bars)applied on the column. A Kromasil KR-100-5-C₁₈ column (250×20 mm, AkzoNobel) and mixtures of acetonitrile/water with 0.1% TFA at a flow rateof 10 mL/min were used for preparative HPLC. Unless stated otherwise,starting materials were commercially available. All solvents andcommercial reagents were of laboratory grade and were used as received.The organic phases from extractions were dried over anhydrous sodiumsulfate if not stated otherwise. Organic phases or solutions wereconcentrated by rotary evaporation. Yields were not optimised.

The Following Method was Used for LC-MS Analysis:

Instrument Agilent 1100; Column Waters Symmetry 2.1×30 mm; Mass APCI;Flow rate 0.7 mL/min; Wavelength 254 or 220 nm; Solvent A: water+0.1%TFA; Solvent B: acetonitrile+0.1% TFA; Gradient 15-95% B 2.7 min, 95% B0.3 min.

The Following Method was Used for GC-MS Analysis:

Instrument Hewlett Packard 5890 Series II; Column Agilent HP-5 (30m×0.32 mm ID); Mass selective detector Hewlett Packard 5971 Series;Pressure 55 kPa He; Oven program 100° C. (3 min) to 300° C., 25° C./min.

Abbreviations:

-   BOC-anhydride di-tert-butyl dicarbonate-   n-BuLi n-butyl lithium-   DCM dichloromethane-   DIPEA N,N-diisopropylethylamine-   DMF N,N-dimethylformamide-   DMSO dimethylsulfoxide-   EtOAc ethyl acetate-   EtOH ethanol-   GC-MS gas chromatography-mass spectrometry-   LDA lithium diisopropylamide-   MeOH methanol-   LC-MS liquid chromatography-mass spectroscopy-   PdCl₂×dppf 1,1′-bis(diphenylphosphino)ferrocene    palladium(II)dichloride-   RT room temperature, normally 20 to 22° C.-   TEA triethylamine-   THF tetrahydrofuran-   TBME tert-butyl methyl ether-   TFA trifluoroacetic acid-   Triflic anhydride trifluoromethanesulfonic anhydride (Tf₂O)

EXAMPLE 1(5)-5-Methyl-5-({[6-[2-(trifluoromethyl)pyrimidin-5-yl]-3,4-dihydroisoquinolin-2(1H)-yl]sulfonyl}methyl)imidazolidine-2,4-dione

[(4S)-4-Methyl-2,5-dioxoimidazolidin-4-yl]methanesulfonyl chloride(0.0295 g, 0.13 mmol) in dry THF (0.60 mL) was added dropwise to astirred solution of6-[2-(trifluoromethyl)pyrimidin-5-yl]-1,2,3,4-tetrahydroisoquinoline(0.039 g, 0.14 mmol), DIPEA (0.034 mL, 0.20 mmol) and dry THF (0.60 mL)at ice-bath temperature. After the addition was complete the solutionwas stirred at RT for 2 h and then taken up in water-brine and extractedtwice with EtOAc. The combined organic phases were washed with brine,dried, filtered and concentrated to give a crude product. Purificationby preparative HPLC afforded 0.050 g (76%) of the title compound as awhite solid.

LC-MS m/z 470 (M+1);

¹H NMR (CD₃CN) δ 9.19 (s, 2H), 8.51 (br s, 1H), 7.62 (s, 1H), 7.61 (dd,1H), 7.36 (d, 1H), 6.33 (br s, 1H), 4.51 (s, 2H), 3.57 (t, 2H), 3.52 (d,1H), 3.42 (d, 1H), 3.04 (t, 2H) and 1.48 (s, 3H) ppm.

The starting materials were prepared as follows:

6-[2-(Trifluoromethyl)pyrimidin-5-yl]-1,2,3,4-tetrahydroisoquinoline

tert-Butyl6-[2-(trifluoromethyl)pyrimidin-5-yl]-3,4-dihydroisoquinoline-2(1H)-carboxylate(0.051 g, 0.13 mmol) was stirred in TFA (1.0 mL) and DCM (1.0 mL) at RTovernight, then concentrated twice, the second time with added toluene(5 mL), to afford the trifluoroacetate salt.

LC-MS m/z 280 (M+1);

¹H NMR (CD₃CN) δ 9.25 (s, 2H), 7.73 (m, 2H), 7.44 (d, 1H), 4.45 (s, 2H),3.56 (t, 2H) and 3.24 (t, 2H) ppm.

The crude product was taken up in 1M sodium carbonate solution (10 mL)and extracted twice with EtOAc. The combined organic phases were washedwith brine, dried, filtered and concentrated to give 0.039 g (100%) ofthe title product as a white solid.

2-(Trifluoromethyl)pyrimidin-5-yl trifluoromethanesulfonate

Triflic anhydride (13.9 g, 85 mmol) in dry DCM (70 mL) was added slowlyto an ice-cold solution of 2-(trifluoromethyl)pyrimidin-5-oI (13.9, 85mmol) (U.S. Pat. No. 4,558,039), DIPEA (16 mL, 93 mmol) and dry DCM (260mL) at such a rate that the temperature was kept between 4° C. and 6° C.After the addition was complete, the solution was stirred for 2.5 h at4° C. and then allowed to warm to RT. Water (50 mL) and 1M phosphoricacid (4.5 mL) were added and the phases were washed and separated. Theorganic phase was washed successively with water and saturated sodiumbicarbonate, dried, filtered and carefully concentrated by rotaryevaporation (pressure 300-400 mbar). The dark-red oil was purified bycolumn chromatography with EtOAc-heptanes (1:8 through 1:4) as eluent togive 22.5 g (90%) of the title product as a colourless oil thatcrystallised in the cold. Alternatively, the product could be purifiedby distillation, b.p. 75-77° C./10 mbar.

¹H NMR (CDCl₃) δ 8.90 (s, 2H) ppm.

tert-Butyl6-[2-(trifluoromethyl)pyrimidin-5-yl]-3,4-dihydroisoquinoline-2(1H)-carboxylate

A 4:1 mixture (0.10 g, 0.28 mmol) of tert-butyl6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3,4-dihydroisoquinoline-2(1H)-carboxylateand tert-butyl8-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3,4-dihydroisoquinoline-2(1H)-carboxylate,2-(trifluoromethyl)pyrimidin-5-yl trifluoromethanesulfonate (0.083 g,0.28 mmol), PdCl₂×dppf (0.0048 g), 2M sodium carbonate (1.1 mL), toluene(4.0 mL) and EtOH (1.0 mL) was purged with dry argon for ten minutesthen heated in a sealed vial at 81° C. for 6 h. The black solution wasfiltered through glass-wool, taken up in water-brine and washed twicewith EtOAc. The combined organic phases were dried, filtered andconcentrated with silica (5 g). Column chromatography withEtOAc-heptanes (1:8 through 1:5) gave 0.051 g (48%) of the title productas white solid.

LC-MS m/z 380 (M+1);

¹H NMR (CDCl₃) δ 9.06 (s, 2H), 7.44 (dd, 1H), 7.38 (br s, 1H), 7.30 (d,1H), 4.66 (s, 2H), 3.71 (t, 2H), 2.95 (t, 2H), and 1.51 (s, 9H) ppm.

tert-Butyl6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3,4-dihydroisoquinoline-2(1H)-carboxylate

A 3:1 mixture (0.49 g, 1.6 mmol) of tert-butyl6-bromo-3,4-dihydroisoquinoline-2(1H)-carboxylate and tert-butyl8-bromo-3,4-dihydroisoquinoline-2(1H)-carboxylate,bis(pinacolato)diborane (0.45 g, 1.8 mmol), PdCl₂×dppf (0.039 g, 0.048mmol), potassium acetate (0.48 g, 4.8 mmol) and DMF (8.0 mL) was heatedat 81° C. overnight. The solvent was evaporated, the residue taken up inwater-brine and washed twice with EtOAc. The organic phase was dried,filtered and concentrated. Column chromatography with EtOAc-heptanes(1:10 through 1:4) gave 0.24 g of a 4:1 mixture of the title product andtert-butyl8-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3,4-dihydroisoquinoline-2(1H)-carboxylate.

¹H NMR (CDCl₃) δ 7.62 (d, 1H), 7.60 (s, 1H), 7.13 (d, 1H), 4.59 (s, 2H),3.64 (t, 2H), 2.85 (t, 2H), 1.50 (s, 9H) and 1.35 (s, 12H) ppm(6-isomer).

¹H NMR (CDCl₃) δ 7.69 (d, 1H), 7.24-7.14 (m, 2H), 4.88 (s, 2H), 3.64 (t,2H), 2.85 (t, 2H), 1.50 (s, 9H) and 1.35 (s, 12H) ppm (8-isomer).

tert-Butyl 6-bromo-3,4-dihydroisoquinoline-2(1H)-carboxylate

6-Bromo-2-(trifluoroacetyl)-1,2,3,4-tetrahydroisoquinoline was preparedin two steps from [2-(3-bromophenyl)ethyl]amine (4.0 g, 20 mmol)following the procedure of Stokker (Tetrahedron Lett. 1996, 37(31),5453-5456). Column chromatography with EtOAc-heptanes (1:10 through 1:6)gave 2.3 g (7.5 mmol) of a 3:1 mixture of6-bromo-2-(trifluoroacetyl)-1,2,3,4-tetrahydroisoquinoline and8-bromo-2-(trifluoro-acetyl)-1,2,3,4-tetrahydroisoquinoline.

¹H NMR (CDCl₃) δ 7.62 (d, 1H), 7.60 (s, 1H), 7.13 (d, 1H), 4.59 (s, 2H),3.64 (t, 2H), 2.85 (t, 2H) and 1.50 (s, 9H) and 1.35 (s, 12H) ppm(6-isomer).

¹H NMR (CDCl₃) δ 7.69 (d, 1H), 7.24-7.14 (m, 2H), 4.88 (s, 2H), 3.64 (t,2H), 2.85 (t, 2H) and 1.50 (s, 9H) and 1.35 (s, 12H) ppm (8-isomer).

The above material was stirred with absolute EtOH (100 mL) and 25%ammonium hydroxide (10 mL) at 60° C. for 4 h. More 25% ammoniumhydroxide (15 mL) was added and stirring continued at RT overnight. Thevolatiles were evaporated to leave the crude amine as a white solid.

LC-MS m/z 212, 214 (M+1).

Dry THF (50 mL) and DIPEA (1.3 mL, 7.5 mmol) were added followed byBOC-anhydride (1.8 g, 8.2 mmol). The mixture was stirred at RTovernight. The volatiles were evaporated and the residue was taken up inwater. The pH was adjusted to 2 with 1M phosphoric acid and the productwas extracted twice with EtOAc. The combined organic phases were washedwith brine made slightly alkaline with saturated sodium bicarbonate,dried, filtered and concentrated. The crude product was purified bycolumn chromatography with EtOAc-heptanes (1:50 through 1:20) to give2.24 g (96%) of a 3:1 mixture of the title product and tert-butyl8-bromo-3,4-dihydroisoquinoline-2(1H)-carboxylate.

LC-MS m/z 256, 258 (M-56);

¹H NMR (CDCl₃) δ 7.31 (dd, 1H), 7.30 (br s, 1H), 6.98 (d, 1H), 4.52 (s,2H), 3.63 (t, 2H), 2.81 (t, 2H) and 1.50 (s, 9H) ppm (6-isomer).

¹H NMR (CDCl₃) δ 7.42 (dd, 1H), 7.12-7.01 (m, 2H), 4.55 (s, 2H), 3.64(t, 2H), 2.84 (t, 2H) and 1.51 (s, 9H) ppm (8-isomer).

EXAMPLE 2(5S)-5-({[6-(4-Chlorophenyl)-3,4-dihydroisoquinolin-2(1H)-yl]sulfonyl}methyl)-5-methylimidazolidine-2,4-dione

(5S)-{[(6-Bromo-3,4-dihydroisoquinolin-2(1H)-yl)sulfonyl]methyl}-5-methyl-imidazolidine-2,4-dione(0.016 g, 0.040 mmol), 4-chlorophenylboronic acid (0.0072 g, 0.045mmol), PdCl₂×dppf (0.0030 g), 2M sodium carbonate (0.15 mL), toluene(0.80 mL) and EtOH (0.20 mL) were stirred in a sealed vial at 95° C. for17 h. The solvent was evaporated and the residue was taken up in water.The solution was acidified with 10% HOAc to pH 6 and then extractedtwice with EtOAc. The combined organic phases were washed withbrine-saturated sodium bicarbonate, dried, filtered and concentrated togive a crude product.

LC-MS m/z 434 (M+1).

Purification by preparative HPLC afforded 0.0080 g (46%) of the titlecompound as a white solid.

¹H NMR (CD₃CN) δ 8.53 (br s, 1H), 7.62 (m, 2H), 7.46 (m, 4H), 7.23 (d,1H), 6.34 (br s, 1H), 4.45 (s, 2H), 3.53 (m, 2H), 3.49 (d, 1H), 3.39 (d,1H), 2.99 (m, 2H) and 1.46 (s, 3H) ppm.

The compounds of Examples 3 and 4 were prepared using the general methodof Example 2.

EXAMPLE 3{4-[2-({[(4S)-4-Methyl-2,5-dioxoimidazolidin-4-yl]methyl}sulfonyl)-1,2,3,4-tetrahydroisoquinolin-6-yl]phenyl}acetonitrile

White solid.

LC-MS m/z 439 (M+1);

¹H NMR (CD₃CN) δ 8.61 (br s, 1H), 7.65 (m, 2H), 7.48 (m, 2H), 7.43 (m,2H), 7.23 (d, 1H), 6.38 (br s, 1H), 4.46 (s, 2H), 3.87 (s, 2H), 3.53 (m,2H), 3.50 (d, 1H), 3.40 (d, 1H), 3.00 (m, 2H) and 1.46 (s, 3H) ppm.

EXAMPLE 4(5S)-5-Methyl-5-{[(6-pyridin-3-yl-3,4-dihydroisoquinolin-2(1H)-yl)sulfonyl]methyl}imidazolidine-2,4-dione

White solid.

LC-MS m/z 401 (M+1);

¹H NMR (CD₃CN) δ 8.98 (br s, 1H), 8.71 (m, 1H), 8.54 (d, 2H), 7.89 (m,1H), 7.56 (m, 2H), 7.34 (m, 1H), 6.34 (br s, 1H), 4.49 (s, 2H), 3.55 (m,2H), 3.52 (d, 1H), 3.41 (d, 1H), 3.03 (m, 2H) and 1.47 (s, 3H) ppm.

The starting material was prepared as follows:

(5S)-5-({[6-Bromo-3,4-dihydroisoquinolin-2(1H)-yl]sulfonyl}methyl)-5-methylimidazolidine-2,4-dione

A 3:1 mixture (0.44 g, 1.4 mmol) of6-bromo-2-(trifluoroacetyl)-1,2,3,4-tetrahydroisoquinoline and8-bromo-2-(trifluoroacetyl)-1,2,3,4-tetrahydroisoquinoline (preparedaccording to Tetrahedron Lett. 1996, 37(31), 5453-5456) was stirred inethanol (10 mL) containing a few drops of 25% ammonium hydroxide at RT.After 2.5 h, the solution was concentrated, dissolved in dry THF (1.0mL) under argon and cooled on an ice-bath. DIPEA (0.41 mL, 2.4 mmol) wasadded followed by a solution of[(4S)-4-methyl-2,5-dioxoimidazolidin-4-yl]methanesulfonyl-chloride (0.27g, 1.2 mmol) and dry THF (1.0 mL). The mixture was stirred at RT for 1 hand then concentrated. The crude product was taken up in water andextracted twice with EtOAc. The combined organic phases were washed withbrine, dried, filtered and concentrated to give 0.55 g of a mixture of(5S)-5-({[6-bromo-3,4-dihydroisoquinolin-2(1H)-yl]sulfonyl}methyl)-5-methylimidazolidine-2,4-dioneand(5S)-5-({[8-bromo-3,4-dihydroisoquinolin-2(1H)-yl]sulfonyl}methyl)-5-methylimidazolidine-2,4-dione.The regioisomers were separated by preparative HPLC.

(5S)-5-({[8-Bromo-3,4-dihydroisoquinolin-2(1H)-yl]sulfonyl}methyl)-5-methylimidazolidine-2,4-dione(eluting first)

Yield: 0.13 g of a white solid.

LC-MS m/z 402/404 (M+1), 419/421 (M+18);

¹H NMR (CD₃CN) δ 8.48 (br s, 1H), 7.48 (m, 1H), 7.21 (m, 1H), 7.14 (m,1H), 6.31 (br s, 1H), 4.36 (s, 2H), 3.48 (m, 4H), 2.95 (m, 2H) and 1.46(s, 3H) ppm.

(5S)-5-({[6-Bromo-3,4-diihydroisoquinolin-2(1H)-yl]sulfonyl}methyl)-5-methylimidazolidine-2,4-dione(eluting second)

Yield: 0.25 g of a white solid.

LC-MS m/z 402/404 (M+1), 419/421 (M+18);

¹H NMR (CD₃CN) δ 8.47 (br s, 1H), 7.38 (m, 1H), 7.36 (m, 1H), 7.08 (m,1H), 6.29 (br s, 1H), 4.36 (s, 2H), 3.48 (m, 2H), 3.47 (d, 1H), 3.37 (d,1H), 2.92 (m, 2H) and 1.45 (s, 3H) ppm.

EXAMPLE 5(5S)-5-({[6-(4-Chlorophenyl)-3,4-dihydro-2,7-naphthyridin-2(1H)-yl]sulfonyl}methyl)-5-methylimidazolidine-2,4-dione

[(4S)-4-Methyl-2,5-dioxoimidazolidin-4-yl]methanesulfonyl chloride(0.086 g, 0.38 mmol) in anhydrous NMP (0.50 mL) was added dropwise to astirred solution of6-(4-chlorophenyl)-1,2,3,4-tetrahydro-2,7-naphthyridine (0.046 g, 0.19mmol), DIPEA (0.066 mL, 0.38 mmol) and anhydrous NMP (1.5 mL) at RT.After the addition was complete the solution was stirred at RT for 1.5h, then diluted with water (1 mL) and purified by preparative HPLC toafford 0.0070 g (8%) of the title compound as a white solid.

LC-MS m/z 435, 436 (M+1);

¹H NMR (DMSO-d₆) δ 10.8 (s, 1H), 8.49 (s, 1H), 8.10 (d, 2H), 8.06 (s,1H), 7.84 (s, 1H), 7.54 (d, 2H), 4.45 (s, 2H), 3.61 (d, 1H), 3.48 (d,1H), 3.47 (t, 2H), 2.98 (t, 2H) and 1.34 (s, 3H) ppm.

The starting materials were prepared as follows:

6-(4-Chlorophenyl)-1,2,3,4-tetrahydro-2,7-naphthyridine

tert-Butyl6-{[(trifluoromethyl)sulfonyl]oxy}-3,4-dihydro-2,7-naphthylidine-2(1H)-carboxylate(0.69 g, 1.8 mmol), 4-chlorophenylboronic acid (0.39 g, 2.5 mmol),PdCl₂×dppf (0.050 g), saturated sodium carbonate (2 mL), EtOH (4 mL) andtoluene (4 mL) were stirred at 80° C. for 6 h. The solution was cooledto RT, taken up in water (10 mL) and extracted with EtOAc (25 mL). Thecombined organic phases were washed with brine, dried, filtered andconcentrated. Purification by column chromatography with EtOAc-heptanes(1:1) as eluent gave 0.065 g (10%) of tert-butyl6-(4-chlorophenyl)-3,4-dihydro-2,7-naphthyridine-2(1H)-carboxylate.

LC-MS m/z 345 (M+1).

This material was dissolved in MeOH (2 mL) and acetyl chloride (0.2 mL)was slowly added. After stirring at 40° C. overnight, the solution wasconcentrated, the residue was taken up in 1M sodium hydroxide (10 mL)and extracted with EtOAc-ether (1:1) (4×30 mL). The combined organicphases were dried, filtered and concentrated to give 0.046 g (100%) ofthe crude title compound.

LC-MS m/z 245 (M+1).

tert-Butyl6-{[(trifluoromethyl)sulfonyl]oxy}-3,4-dihydro-2,7-naphthyridine-2(1H)-carboxylate

Crude 3-methoxy-2,7-naphthyridine (prepared from 4.4 mmol of6-methoxy-4-[(trimethylsilyl)ethynyl]nicotinaldehyde) was hydrogenated(30 psi pressure) at RT over PtO₂ (approx. 0.1 g) in HOAc (25 mL) for2.5 h. The solution was filtered through a Celite pad and the clearfiltrate was concentrated by freeze-drying to give crude6-methoxy-1,2,3,4-tetrahydro-2,7-naphthyridine as the acetate salt.

LC-MS m/z 165 (M+1).

This material was refluxed in 48% hydrobromic acid for 10 h. Thevolatiles were evaporated and the residue was dried under vacuum and 45°C. to give approx. 0.70 g. of crude5,6,7,8-tetrahydro-2,7-naphthyridin-3-ol hydrobromide.

LC-MS m/z 151 (M+1).

This material (approx. 4.8 mmol) was dissolved in water (13 mL) andtreated with THF (33 mL), Et₃N (0.85 mL, 6.0 mmol) and BOC-anhydride(1.6 g, 7.3 mmol) at RT. After stirring at the same temperature for 6 hthe solution was concentrated to one third of its original volume andthe residue was taken up in water and extracted three times with EtOAc.The combined organic phases were dried, filtered and concentrated togive 0.80 g (67% crude yield) of tert-butyl6-hydroxy-3,4-dihydro-2,7-naphthyridine-2(1H)-carboxylate as a whitesolid.

LC-MS m/z 251 (M+1), 195 (M-55).

This material (approx. 5.4 mmol) was dissolved in a two-phase system oftoluene (20 mL) and 30% aqueous tripotassium orthophosphate (20 mL) andtreated with triflic anhydride (1.6 mL, 6.8 mmol) at 4° C. [Org. Lett.2002, 4(26), 4717-4718]. The ice-bath was removed and the stirring wascontinued for 2 h at RT after which the two phases were separated. Theaqueous phase was washed once with toluene. The combined organic phaseswere washed with brine, dried and concentrated. Purification by columnchromatography with EtOAc-heptanes (2:1) as eluent gave 0.45 g (17%yield) of the title product.

LC-MS m/z 383 (M+1), 283 (M-99).

3-Methoxy-2,7-naphthyridine

To a stirred solution of N,N′-trimethylethylenediamine (1.9 mL, 15 mmol)in anhydrous THF (65 mL) under argon at −70° C. was slowly added 1.6Mn-BuLi in hexanes (9.0 mL, 14 mmol). After stirring at −70° C. for 15minutes, 6-methoxy-nicotinaldehyde (1.3 g, 9.8 mmol) was added dropwise.After the addition was complete, stirring was continued at 70° C. foranother 15 minutes. Then 1.6M n-BuLi in hexanes (10 mL, 16 mmol) wasadded dropwise and stirring continued at −45° C. for 4 h. The solutionwas cooled to −70° C. and then a solution of iodine (3.0 g, 12 mmol) andanhydrous THF (25 mL) was added dropwise. When the addition wascomplete, stirring was continued at −70° C. for 30 minutes and then atRT for 3 h. The crude product was taken up in ether (40 mL) and washedsuccessively with saturated ammonium chloride (2×40 mL) and 5% sodiumthiosulfate (2×20 mL). The organic phase was dried, filtered andconcentrated. Purification by column chromatography with EtOAc-heptanes(1:1) as eluent gave 0.41 g (15% yield) of4-iodo-6-methoxynicotinaldehyde.

LC-MS m/z 264 (M+1);

¹H NMR (CDCl₃) δ 9.95 (s, 1H), 8.53 (s, 1H), 7.32 (s, 1H) and 3.98 (s,3H) ppm.

4-Iodo-6-methoxynicotinaldehyde (0.41 g, 1.6 mmol),trimethylsilylacetylene (0.35 mL, 2.8 mmol), PdCl₂(PPh₃)₂ (catalyticamount), CuI (catalytic amount), TEA (2 mL) and THF (10 mL) were stirredat 60° C. for 2 h. The volatiles were evaporated and the residue wastaken up in water and extracted with ether. The organic phase was dried,filtered and concentrated. Purification by column chromatography withEtOAc-heptanes (1:3) as eluent gave 0.25 g (68% yield) of6-methoxy-4-[(trimethylsilyl)ethynyl]nicotinaldehyde.

LC-MS m/z 234 (M+1);

¹H NMR (CDCl₃) δ 10.4 (s, 1H), 8.73 (s, 1H), 6.84 (s, 1H), 4.03 (s, 3H)and 0.30 (s, 9H) ppm.

6-Methoxy-4-[(trimethylsilyl)ethynyl]nicotinaldehyde (0.25 g, 1.1 mmol)and 7M ammonia in MeOH (5 mL) were stirred in a sealed vial at 80° C.overnight. The solution was concentrated, taken up in saturated sodiumcarbonate and extracted with ether. The organic phase was dried,filtered and concentrated to give 0.20 g of the title product.

GC-MS m/z 160 (M);

¹H NMR (CDCl₃) δ 9.41 (s, 1H), 9.27 (s, 1H), 8.47 (d, 1H), 7.64 (d, 1H),7.03 (s, 1H) and 4.12 (s, 3H) ppm.

PHARMACOLOGICAL EXAMPLE Isolated Enzyme Assays

MMP12

Recombinant human MMP12 catalytic domain may be expressed and purifiedas described by Parkar A. A. et al, (2000), Protein Expression andPurification, 20, 152. The purified enzyme can be used to monitorinhibitors of activity as follows: MMP12 (50 ng/ml final concentration)is incubated for 60 minutes at room temperature with the syntheticsubstrate Mca-Pro-Cha-Gly-Nva-His-Ala-Dpa-NH₂ (10 μM) in assay buffer(0.1M “Tris-HCl” (trade mark) buffer, pH 7.3 containing 0.1M NaCl, 20 mMCaCl₂, 0.020 mM ZnCl and 0.05% (w/v) “Brij 35” (trade mark) detergent)in the presence (10 concentrations) or absence of inhibitors. Activityis determined by measuring the fluorescence at λex 320 nm and λem 405nm. Percent inhibition is calculated as follows:% Inhibition is equal to the[Fluorescence_(plus inhibitor)−Fluorescence_(background)] divided by the[Fluorescence_(minus inhibitor)−Fluorescence_(background)]MMP8

Purified pro-MMP8 is purchased from Calbiochem. The enzyme (at 10 μg/ml)is activated by p-amino-phenyl-mercuric acetate (APMA) at 1 mM for 2.5h, 35° C. The activated enzyme can be used to monitor inhibitors ofactivity as follows: MMP8 (200 ng/ml final concentration) is incubatedfor 90 minutes at 35° C. (80% H₂O) with the synthetic substrateMca-Pro-Cha-Gly-Nva-His-Ala-Dpa-NH₂ (12.5 μM) in assay buffer (0.1M“Tris-HCl” (trade marl) buffer, pH 7.5 containing 0.1M NaCl, 30 mMCaCl₂, 0.040 mM ZnCl and 0.05% (w/v) “Brij 35” (trade mark) detergent)in the presence (10 concentrations) or absence of inhibitors. Activityis determined by measuring the fluorescence at λex 320 nm and λem 405nm. Percent inhibition is calculated as follows:% Inhibition is equal to the[Fluorescence_(plus inhibitor)−Fluorescence_(background)] divided by the[Fluorescence_(minus inhibitor)−Fluorescence_(background)]MMP9

Recombinant human MMP9 catalytic domain was expressed and then purifiedby Zn chelate column chromatography followed by hydroxamate affinitycolumn chromatography. The enzyme can be used to monitor inhibitors ofactivity as follows: MMP9 (5 ng/ml final concentration) is incubated for30 minutes at RT with the synthetic substrateMca-Pro-Cha-Gly-Nva-His-Ala-Dpa-NH₂ (5 μM) in assay buffer (0.1M“Tris-HCl” (trade mark) buffer, pH 7.3 containing 0.1M NaCl, 20 mMCaCl₂, 0.020 mM ZnCl and 0.05% (w/v) “Brij 35” (trade mark) detergent)in the presence (10 concentrations) or absence of inhibitors. Activityis determined by measuring the fluorescence at λex 320 nm and λem 405nm. Percent inhibition is calculated as follows:% Inhibition is equal to the[Fluorescence_(plus inhibitor)−Fluorescencebackgyound] divided by the[Fluorescence_(minus inhibitor)−Fluorescence_(background)]MMP14

Recombinant human MMP14 catalytic domain may be expressed and purifiedas described by Parkar A. A. et al, (2000), Protein Expression andPurification, 20, 152. The purified enzyme can be used to monitorinhibitors of activity as follows: MMP14 (10 ng/ml final concentration)is incubated for 60 minutes at room temperature with the syntheticsubstrate Mca-Pro-Cha-Gly-Nva-His-Ala-Dpa-NH₂ (10 μM) in assay buffer(0.1M “Tris-HCl” (trade mark) buffer, pH 7.5 containing 0.1M NaCl, 20 mMCaCl₂, 0.020 mM ZnCl and 0.05% (w/v) “Brij 35” (trade mark) detergent)in the presence (5 concentrations) or absence of inhibitors. Activity isdetermined by measuring the fluorescence at λex 320 nm and λem 405 nm.Percent inhibition is calculated as follows: % Inhibition is equal tothe [Fluorescence_(plus inhibitor)−Fluorescence_(background)] divided bythe [Fluorescence_(minus inhibitor)−Fluorescence_(background)].

A protocol for testing against other matrix metalloproteinases,including MMP9, using expressed and purified pro MMP is described, forinstance, by C. Graham Knight et al., (1992) FEBS Lett., 296(3),263-266.

MMP19

Recombinant human MMP19 catalytic domain may be expressed and purifiedas described by Parkar A. A. et al, (2000), Protein Expression andPurification, 20:152. The purified enzyme can be used to monitorinhibitors of activity as follows: MMP19 (40 ng/ml final concentration)is incubated for 120 minutes at 35° C. with the synthetic substrateMca-Pro-Leu-Ala-Nva-Dpa-Ala-Arg-NH₂ (5 μM) in assay buffer (0.1M“Tris-HCl” (trade mark) buffer, pH 7.3 containing 0.1M NaCl, 20 mMCaCl₂, 0.020 mM ZnCl and 0.05% (w/v) “Brij 35” (trade mark) detergent)in the presence (5 concentrations) or absence of inhibitors. Activity isdetermined by measuring the fluorescence at λex 320 nm and λem 405 nm.Percent inhibition is calculated as follows: % Inhibition is equal tothe [Fluorescence_(plus inhibitor)−Fluorescence_(background)] divided bythe [Fluorescence_(minus inhibitor)−Fluorescence_(background)].

The following table shows data for a representative selection of thecompounds of the present invention. TABLE hMMP12 hMMP9 hMMP14 CompoundIC₅₀ (nM) IC₅₀ (nM) IC₅₀ (nM) Example 1 10.4 29.3 >10000 Example 2 1.43.5 415 Example 5 7 8.3 1990

1. A compound of formula (I) or a pharmaceutically acceptable saltthereof

wherein R¹ represents H, halogen, CF₃ or CH₂CN; R² represents C1 to 3alkyl; and A, A¹ and B each independently represent CH or N;
 2. Acompound according to claim 1, wherein R¹ represents chloro.
 3. Acompound according to claim 1, wherein R¹ represents CF₃.
 4. A compoundaccording to claim 1, wherein R² represents methyl or ethyl.
 5. Acompound according to claim 1, wherein A and A¹ each represent N.
 6. Acompound according to claim 1 which is selected from the groupconsisting of:(5S)-5-methyl-5-({[6-[2-(trifluoromethyl)pyrimidin-5-yl]-3,4-dihydroisoquinolin-2(1H)-yl]sulfonyl}methyl)imidazolidine-2,4-dione;(5S)-5-({[6-(4-chlorophenyl)-3,4-dihydroisoquinolin-2(1H)-yl]sulfonyl}methyl)-5-methylimidazolidine-2,4-dione;{4-[2-({[(4S)-4-methyl-2,5-dioxoimidazolidin-4-yl]methyl}sulfonyl)-1,2,3,4-tetrahydroisoquinolin-6-yl]phenyl}acetonitrile;(5S)-5-methyl-5-{[(6-pyridin-3-yl-3,4-dihydroisoquinolin-2(1H)-yl)sulfony]methyl}imidazolidine-2,4-dione;(5S)-5-({[6-(4-chlorophenyl)-3,4-dihydro-2,7-naphthyridin-2(1H)-yl]sulfonyl}methyl)-5-methylimidazolidine-2,4-dione;and pharmaceutically acceptable salts thereof.
 7. A process for thepreparation of a compound of formula (I) as defined in claim 1 or apharmaceutically acceptable salt thereof which comprises: a) reaction ofa compound of formula (II)

where R² is as defined in formula (I) and L¹ represents a leaving group,with a compound of formula (III) (or a salt thereof)

wherein R¹, A, A¹ and B are as defined in formula (I); or b) reaction ofa compound of formula (V)

wherein R² and B are as defined in formula (I) and LG is a leavinggroup; with a boronic acid derivative of formula (XII)

wherein R¹, A, A¹ and B are as defined in formula (I); or c) reaction ofa compound of formula (IX)

wherein R¹, A, A¹ and B are as defined in formula (I); with ammoniumcarbonate and potassium cyanide; and optionally thereafter forming apharmaceutically acceptable salt thereof.
 8. A pharmaceuticalcomposition comprising a compound of formula (I) or a pharmaceuticallyacceptable salt thereof as claimed in claim 1 in association with apharmaceutically acceptable adjuvant, diluent or carrier.
 9. A processfor the preparation of a pharmaceutical composition comprising acompound of formula (I) or a pharmaceutically acceptable salt thereof asclaimed in claim 1 in association with a pharmaceutically acceptableadjuvant, diluent or carrier, the method comprising mixing a compound offormula (I) or a pharmaceutically acceptable salt thereof as defined inclaim 1 with a pharmaceutically acceptable adjuvant, diluent or carrier.10. (canceled)
 11. A method of treating an obstructive airways disease,the method comprising administering to a subject a compound of formula(I) or a pharmaceutically acceptable salt thereof as claimed in claim 1.12. The method according to claim 11, wherein the obstructive airwaysdisease is asthma or chronic obstructive pulmonary disease.
 13. A methodof treating rheumatoid arthritis, osteoarthritis, atherosclerosis,cancer or multiple sclerosis, the method comprising administering to asubject, a compound of formula (I), or a pharmaceutically acceptablesalt thereof, as claimed in claim
 1. 14. A method of treating a diseaseor condition mediated by MMP12 and/or MMP9 which comprises administeringto a patient a therapeutically effective amount of a compound of formula(I) or a pharmaceutically acceptable salt thereof as claimed in claim 1.15. (canceled)